重组大肠杆菌右旋糖酐蔗糖酶的表达条件优化

通过设计正交实验,考察了培养基中各组分及其浓度对右旋糖酐蔗糖酶工程菌Escherichia coli BL21(DE3)/pET28-dexYG诱导产酶结果的影响。在获得最佳培养条件的基础上,考察温度、蔗糖浓度和pH值对右旋糖酐产量的影响。结果表明:菌浓OD600达到2.0时,加入异丙基硫代-β-D-呋喃半乳糖苷(IPTG)至0.25mmol/L,25°C诱导培养4h,产酶活力最高,达到110.16U/mL,蔗糖浓度对产量的影响比较显著。研究结果得到高效表达的培养条件,为实现该酶的工业化应用打下了基础。

Optimization of culture conditions for recombinant dextransucrase expression

We optimized the medium for recombinant dextransucrase expression in engineering strain Escherichia coli BL21 (DE3)/pET28-dexYG by an Orthogonal experiment. After the medium had been decided, we studied the effect of temperature, sucrose concentration and pH value on the yield. The results indicated that optimal conditions were adding IPTG of 0.25 mmol/L when OD600 reached 2.0 and cultivation lasted for 4 h at 25°C. Under the selected medium and these conditions, the dextransucrase activity expressed by the engineering strain was high activity. Maximal activity reached 110.16 U/mL sucrose concentration effects the dextran yield grately. The results for dextransucrase expression would provide foundation for industrial application of dextransucrase.